Even the Comet rubber powered stick and tissue kits left things to be desired that were at least fixed in Goldberg, Midwest and Top Flite designs. That was things like landing gear. If you followed Comet's weak designs, the landing gear would be ripped out upon first flight landing. I fixed their 18" span P-40 Warhawk plan by making a non-scale music wire landing gear fastened to a fuselage bulkhead just in front of the wing leading edge.

Plans required a modeller to have some prior knowledge of building, to fill in the gaps. It was an incentive to buy the magazine from which the plan issued from. Back then, magazines weren't expensive due to their worldwide circulation in very large numbers of copies printed. Though not perfect, the article instructions did help to cover some bases that the plans did not show or clearly explain.

I have an old Flying Models plan from the 1960's of the Aeronca C-3, about 50 inch span for rudder only and throttle control using a cross scavenge .15 engine. It does not have clear enough details on how the wing saddle above the cocpit is made, to adequately hold the wing in place with rubber bands. But, I bought the plan on clearance from FM back in the late 1970's. It is perhaps a best example of vagueness on details. Unfortunately, have not found it on-line as to obtain the FM article on it.

This is where resorting to other similar C-3 designs helps one to fill in details to make it work.